Jesus Had to Overcome the Veil
When Jesus was born, “the veil of forgetfulness common to all who are born to earth, by which the remembrance of primeval existence is shut off” was cast over him. (Talmage, Jesus the Christ, p. 111.) In the premortal world, Jesus had stood as “one like unto God” (Abraham 3:24), “more intelligent than they all” (Abraham 3:19), meaning all the other created spirits. But although his capacity was greater than that of any other, and he was designated to become the Only Begotten Son, still he was meek and humble; and he condescended to have a veil cast over him and to have the knowledge of his glory and power in premortality blocked from his mind at birth.
President Joseph Fielding Smith further explained:
“Without a doubt, Jesus came into the world subject to the same condition as was required of each of us—he forgot everything, and he had to grow from grace to grace. His forgetting, or having his former knowledge taken away, would be requisite just as it is in the case of each of us, to complete the present temporal existence.” (Doctrines of Salvation, 1:33. Italics added.)
Can you see that although Jesus was the greatest spirit to come to the earth, he also had greater trials than anyone in the earth?
It is improper to suppose that Jesus was not tested and tempted equal to his great capacity. The fact that he was sinless and that he resisted every temptation does not make it any less a fact that he was subject to temptations. He knows how difficult temptations are, because he experienced bitter temptations; but he resisted them all. Read what King Benjamin taught in Mosiah 3:7.
Jesus suffered temptations far beyond what men could endure; he confronted the powers of evil and won. But because he had to resist temptations, he understands the effort man must make to resist temptation. Again, as Paul said: “For in that he himself hath suffered being tempted, he is able to succour them that are tempted.” (Hebrews 2:18; 4:15.)
Jesus was perfectly obedient, and because he was, “he received all power, both in heaven and on earth.” (D&C 93:17. Emphasis added.) But Jesus did not receive this great power and glory all at once. He received it piecemeal, step by step, degree by degree, “line upon line, precept upon precept” (D&C 128:21) until he received a fulness of the glory of the Father (see D&C 93:11–17). (The Life and teachings of Jesus and his apostles, chapter 3: The Son of the Eternal Father)